dispenser

[Robovergne] prides himself on the beautiful reef aquarium that he has set up in his home. These sorts of water displays require constant maintenance due to the mineral requirements of living coral. Rather than add mineral solutions manually, he decided to build a nano-doser using espresso machine pumps (Google Translation).

These vibration pumps run on mains voltage, so he had several options as far as how to control them. Using relays would likely make things pretty noisy, so he chose to use a zero crossing detection circuit to precisely control the pumps’ duty cycles and output.

His setup uses a PIC to control everything from the zero crossing circuit to the display LCD. An amount of product and the distribution time frame are entered using a handful of buttons mounted on the front of his control box, leaving the PIC to do the heavy lifting. It will calculate the proper length of time to run the pump based on several factors, including fluid viscosity and height of release.

It really is an impressive system, and while his needs are very precise, we imagine this sort of setup would be quite useful in building less complicated dispensers, such as those found in an automated bar.

The only thing that was bothering [John] is that he wasn’t too keen on keeping his noisy and large air compressor in his workshop, so he set off to find a different way to provide compressed air to the device. He settled on air dusters like those used for cleaning the crumbs out of your keyboard, but he needed to find a way to reliably get the air to his solder dispenser. He heated the air can’s nozzle until he was able to screw his dispenser’s hose barb into it, creating a tight seal. The modified nozzle was reattached to the can and placed in a simple jig that keeps the nozzle held down continuously.

[John] fired up his dispenser, and the 80 psi coming from the duster was plenty to get the solder paste flowing. Sure the rig might not be the most high tech solution, but we think it’s a pretty good means of getting quiet compressed air anywhere you need it.

Solving the age old problem of… wait, what problem are they solving? These students at UC Berkeley have built a toilet paper dispenser prototype. Not only does it meter out an exact amount for you, it will fold it and cut it as well. They mention this being the perfect accessory for a high tech bathroom, and we can agree. To be serious though, in public places, metering out limited amounts of toilet paper at a time could possibly result in major cost savings. We think the next prototype should have different preference settings such as; wadded, folded, or wrapped around your hand. Anyone else’s mind suddenly filled with unpleasant imagery?

Reader, [Andres Leon], has two adorable cats with very specific dietary needs. Instead of altering his schedule, he donned his hacking hat and designed a very solid cat food dispenser. The dispenser consists of a rotating drum with a slot in it and a PVC pipe Y-fitting to distribute the food evenly. The brains of the machine is an Arduino Deumillanove and an XBee module. The unit can be controlled by a web interface or it can run completely standalone. [Andres] ran into a problem where the drum’s resistance to turning varied based on how much food was inside. He solved this with a clever laser position indicator. A piece of plywood is lined up with the slot at the top so that whenever the slot is facing up it keeps the laser from shining on a photoresistor. The cats were afraid of the servo noise at first, but now they run to their bowls whenever they hear it.

[Andrew] made this DVD dispenser for his senior project in high school. It is using an ATmega8515 for the brains, and a custom coded driver for the LCD. As you can see in the video, after the break, you can select a DVD by various identifiers such as genre or title. It then pushes that DVD out of the rack so you can grab it. Right now, all the DVDs have to be placed in predetermined positions, but it’s not a bad start at all. Thanks for sending this in [Andrew].